An ODST ends up on an un-mapped sector of the universe. He discovers a world that is inhabited by humans while he was tracking down a damaged Covenant Corvette which was carrying a valuable object that belonged to the UNSC.

Equestria has been at war for three years against the Griffin Kingdom. When the alien ship crashes the Equestrians discovered that they are not alone. When the ODST encounters the natives he learns that no matter where he goes war is still the same.

ALL MLP characters Humanized. Equestria and the rest of the world have achieved certain inventions. Cars, Planes, Phones and stuff like that.
Sorry for the terrible description.
HALO belongs to bungie
MLP:FIM belong to hasbro
coverart image is by johnjoseco